Jigsaws are a well known type of reciprocating saw. The jigsaw typically comprises an electric motor which drives a reciprocating shaft via a gearbox. The shaft comprises a blade clamp disposed at one end thereof into which a cutting or sawing blade can be disposed. The blade held by the clamp extends through an aperture in a base plate. During use, the base plate is placed on a work-piece such that the saw blade engages an edge of the work-piece. Activation of the motor causes the blade to reciprocate and the application of a forward directed force by a user causes the blade to start cutting the work-piece.
The saw blades are typically arranged such that their cutting stroke occurs during the upward motion of the blade towards the jigsaw's body. As a result, debris produced by the cutting action of the blade can be thrown onto the work-piece during operation of the saw. The debris can obscure markings made on the work-piece by the user prior to cutting the work-piece, for guiding the cut. Thus, the user might have to manually blow or brush debris away from the cut area in order to keep sight of the markings during operation.
The use of an airflow generated by the jigsaw to remove debris from the work-piece is known. Many schemes use airflow generated by a fan disposed on the electric motor. The air is primarily used to cool the motor or gearbox but it can then be directed by conduits formed in the jigsaw's body to an exhaust port where the air flows towards the area of the work-piece being cut. Debris entrained in the airflow is removed from the immediate area of the work-piece being cut, thereby keeping that area largely free of obscuring debris.
It has been found to be advantageous to blow the debris away from the cut area in a direction which does not cause the debris to be moved into an area in front of the jigsaw and still on the cut line. For instance, EP 1601487 describes an arrangement where the air is directed across the cut direction of the jigsaw.
A dust shroud system is described in EP 0347631 which comprises a hood arranged to cover the entire front portion of a jigsaw, including the saw blade, blade clamp and reciprocating shaft.